Frequently unrecognised, PAD is associated with reduced quality of life and an increased mortality rate because of a greater propensity for fatal ischaemic events. PAD commonly coexists with coronary and cerebrovascular disease and is associated with poorer outcomes in such patients. The Edinburgh Claudication Questionnaire (ECQ) and the ankle–brachial index (ABI) are screening methods to identify the presence of PAD. This study used these methods to estimate the rate of previously undiagnosed PAD and to validate the ECQ against ABI in a Canadian outpatient population with manifest cerebrovascular or coronary disease.


At a regular office visit, patients completed the ECQ and were categorised as ECQ(+) or ECQ(−). All ECQ(+) and a randomly selected 25% of ECQ(−) patients were referred for ABI measurement. An ABI < 0.9 was considered positive. The prevalence of PAD in the patient population and the sensitivity and specificity of the ECQ score against the ABI were assessed.


Of 2235 patients enrolled, 815 were selected for an ABI [ECQ(−), n = 478; ECQ(+), n = 337]. Extrapolated PAD prevalence in the total population was 12.3% (highest arterial pressure [HAP] method) and 20.8% (lowest arterial pressure [LAP] method), with a significantly higher prevalence found in diabetic patients than non-diabetic patients (p < 0.0001). Because ECQ is only a measure of symptomatic disease, it had poor sensitivity (35.3% and 25.8%), but high specificity (88.2% and 88.3%) using the HAP and LAP methods of ABI measurement, respectively.


Undiagnosed PAD is common in stable outpatients with a prior history of manifest cardiovascular disease, particularly in those with diabetes. The ECQ does not possess the diagnostic value of the ABI in detecting PAD in this high-risk population, but may be useful to raise suspicion of PAD to be confirmed by ABI assessment.